Electromagnetic device



A. H. PACKER AND F. H. PATTEN. ELECTROMAGNETIC DEVICE. APPLICATION FILED JAN. 16. 1919.

1,354,208. PatentedSe it. 28,1920.

WITNESSES: INVENTORS Alfred H. Packer- Fra r clls hf Paffen ms States, and avresident of Edgewood Park, in the county of Allegheny and State of UNITED 1 STATES PATENT oF'FicE.

ALFRED H. PACKE'B, or PITTSBURGH, AND FRANCIS H. PATTEN OF nnenwoon PARK PENNSYLVANIA, AssIGNons To WESTINGHOUSE ELECTRIC AND MANUFAGTUR: ING COMPANY, A CORPORATION or PENNSYLVANIA.

ELECTROMAGNETIC DEVICE.

To all whom it may concern:

Be it known that we, ALFRED H. PACKER,

ghen and State of ennsylvania, and FR N- PATTEN, a citizen of the United Pennsylvania, have invented a new and use: ful Improvement in Electromagnetic Devices, of which the following is a specification.

' Our invention relates to electromagnetic devices and particularly to electromagnetic devices which are subjected to. extreme temperature changes, such as the control magnets in voltage regulators for automobile generators.

One object of our invention is to proyide an electromagnet, having a spring-biased armature controlled thereby, that shall be compensated for all temperature changes which may be efi'e'cted in the energizing coil, whereby the balanced relation between the magnetic effect of the coil and the spring associated with the armature shall be maintained unchanged, notwithstanding any temperature changes to which the apparatus may be subjected.

In many electromagnetic devices and particularly in delicately adjusted devices, such as the control magnets in voltage regulators, considerable trouble has been experienced, by reason of the changes in resistance of the energizing coils, which is caused by the various temperature changes to which the devices are subjected. Thus, in the control magnet of the voltage regulator suitable for an automobile-lighting circuit, a pivotally mounted armature is biased by some suitable spring member which opposes the action of the energizing coil, and any change in temperature to which the device is subjected will materially change the resistance of the energizing coil and, accordingly, the magnetic effect on the armature without causing any material change in the eflect of the spring member on the armature. Accordingly, the relation of the magnetic effect to the spring efi'ect upon the armature Specification of Iletters Patent.

Patented Sept. '28, 1920.

Application filed January 16, 1919. Serial No. 271,489.

is disturbed or changed In a manner to interfere with the operativeness of the regulator.

has been proposed to construct the sprlng member, which biases the armature, 0t two metals having different coeflicients oi expansion but such a structure has proved to be ineffective in operation for a number of reasons. ,The spring which. is mounted on the armature must be made thin to provide flexibility for opposing the magnetic 'efle ct of the energizing coil and, if the spring s made thin enough for such purpose, it is practically impossible to construct 1t pr strips of difierent metals. Such springs soon lose their shape and become permanently deformed by reason of the loads impressed on them.

in an electromagnetic device constructed 1n accordance with our inventioman armature, which is attracted by an energizing coil, is provided with a spring which engages. a stop member tooppose the action of the energizing coil, and, in place of constructing the armature spring of different metals having different coefficients of expansion, the stop member is provided with a thermal element which compensates for the efi'ect of any temperature change in the energizing coil. lhus, the thermal element of the stop member is bent by changes in temperature. and, accordingly, varies the tension on the armature spring member in accordance with the changes in resistance to which the energizing coil is subjected by reason of the changes in temperature.

In the accompanying drawing, Figure 1 is a side elevational view'of the main control magnet of a voltage regulator constructed in accordance with our invention, and Fig. 2 is a bottom plan view of the control magnet illustrated in Fig. 1.

Referring to thevdrawing, a control magnet 1 is illustrated suitable for use in a voltage regulator of an automobile -lighting 3 of magnetic material connected thereto in a suitable manner, as by means of a nut 4:, which serves as a' core member for supporting an energizing coil 5.- An armature 6,.which is pivotally mounted on one arm 7 in 'any suitable manner, such as by means. of a screw 8, for engaging an armature spring member 9 to oppose the magnetic effect of the energizing coil 5.

The stop member 7 embodles a strip 10 of relatively heavy material wh1ch 1s not flexible and which is attached to the frame 2 by the screw 8. A thermal unit 11, which is attached to the strip 10 in any suitable I manner, as by riveting or welding, is provided for engaging the armature spring 9, and for varying the tension on the armature spring in accordance with the temperature changes to which the electrom'agnet is sub- 'jected. The thermal element essentially comprises strips of metals having different coefficients of expansion and, preferably,

strips composed of steel and nickel, and is bent in a direction to compensate the spring 9 for any temperature changes to which the energizing coil 5 is subjected. It may be noted that, by reason of the limited amount of space available on an auomobile, it is necessary to confine the voltage-regulator mechanism of the lighting system to such close quarters that the same is'subjected at times to very high temperatures, for which correction must be made in order to maintain the operativeness of. the regulator.

The armature dis further provided with a main contact member 12 that engages an auxiliary contact member 13, which is mounted upon the frame 2 in any suitable manner. The contact members 12 and 13 are intermittently operated by a cam member 14 mounted upon a rotating shaft 15 in such manner as that described in the copendin application of John B. Dyer, above referre to. Inasmuch as our invention chiefly relates to J the means for compensating the electromagnet for temperature changes, a further description ofthe regulator is deemed unnecessary.

Although we have described the thermal element 11 as being composed of strips of nickel and steel, it is to be understood that the same may be composed of any metals which have different coefficients of expansion and which expand at different rates when subjected to temperature changes.

Modifications in the. mechanism, and in. the arrangement and location of parts may member being composed of two metals havaeaaaee be made within the spirit and scope of our invention, and such modifications are intended to be covered by the appended claims.

We claim as our invention:

1. In an electromagnetic device, an ener-' gizing coil, a'pivotally mounted armature controlled by said coil, and a resilient stop member mounted independently of, and engaging said armature, said member having a portion'thereof composed of two metals having different coefiicients of expansion.

2. In an electromagnetic device, an energizing coil, an armature controlled by said coil, and a stbp member mounted independently of, and engaging said armature, said ing diiferent'coefficients of expansion.

3. In an electromagnetic device, an energizing coil, a pivotally mounted armature controlled by said coil, and a st0p.member mounted independently of, and engaging said armature, said member having a portion thereof composed of strips of nickel and steel.

4:. In an electromagnetic device, an energizing coil, a pivotally mounted armature controlled by said coil, a stop member, and a spring member mounted on said armature and engaging said stop member to oppose the magnetic action of said coil, said stop member comprising a strip composed of metals having different coefficients of expansion which bends in a direction to change the tension on said spring member in accordance with temperature changes.

5. In an electromagnetic device, an energizing coil, an armature controlled by said coil, a resilient member for biasing the armature away from said coil, and a stop member engaging said resilient member and composed of two metals having different co- 10;, efiicients of expansion.

6. In an electromagnetic device, an energizing coil, a pivotally mounted armature controlled by said coil, a pair of contact members operated by said armature, a stop 110 member, a resilient member mounted on said armature and coacting with said stop member to initially bias the contact mem bers into engagement with each other, said stop member having a portion thereof com- 115 posed of metals having different coefficients of expansion to correct for changes of tem- 'perature in said energizing winding.

7. In an electromagnetic device, an energizing coil, a pivotally mounted armature operated by said coil, a stop member, and aresilient member mounted on the armature and engaging the stop member in a manner to bias the armature away from said coil, said stop member having a portion thereof 1.25

thereof composed of relatively heavy strips 10 of difierent metals having difierent coefiicients of expansion to compensate for temperature changes in said coil.

In testimony whereof, we have hereunto subscribed our names this 27th day of Dec, 15

ALFRED H. PA'CKER. FRANCIS H. PATTEN. 

